Control for the lateral adjustment of a track working tool assembly

ABSTRACT

The lateral adjustment of a track tamping unit is controlled by a sensor associated with the unit and arranged to sense the lateral position of the track in respect of the unit as the tamper moves on the track rails. The sensor produces electrical control signals corresponding to the sensed track deviations, and an adjustable control device for the track tamping unit drive is electrically connected to the sensor and receives the control signals. The signals adjust the control device for moving the track tamping unit laterally in response to the control signals.

United States Patent Plasser et al.

[ Dec. 18, 1973 CONTROL FOR THE LATERAL ADJUSTMENT OF A TRACK WORKING TOOL ASSEMBLY Inventors: Franz Plasser; Josef Theurer, both of Johannesgasse 3, Vienna, Austria Filed: Dec. 30, 1971 App]. No.: 214,070

[30] Foreign Application Priority Data Feb. 19, 1971 Austria 1458 [52] U.S. Cl. 104/12 [51] Int. Cl E01b 27/16 [58] Field of Search 104/7, 8, l2, l3, l04/ l4 [56] References Cited UNITED STATES PATENTS 3,401,642 9/1068 Fisher lO4/7 B 3,534,687 lO/l970 Plasser et al 104/12 3,426,698 2/l969 Foxx et al. 3,504,635 4/1970 Stewart et al 104/12 Primary Examiner-Gerald M. Forlenza Assistant ExaminerRichard A. Bertsch Attorney-Kurt Kelman [57] ABSTRACT The lateral adjustment of a track tamping unit is controlled by a sensor associated with the unit and arranged to sense the lateral position of the track in respect of the unit as the tamper moves on the track rails. The sensor produces electrical control signals corresponding to the sensed track deviations, and an adjustable control device for the track tamping unit drive is electrically connected to the sensor and receives the control signals. The signals adjust the control device for moving the track tamping unit laterally in response to the control signals.

10 Claims, 7 Drawing Figures CONTROL FOR THE LATERAL ADJUSTMENT OF A TRACK WORKING TOOL ASSEMBLY The present invention relates to an apparatus for controlling the lateral adjustment of a track working tool assembly, such a track tamping unit, mounted on the frame of a track working machine for lateral movement transversely of the track. The machine frame is mounted for mobility on the track rails and a drive is provided for laterally moving the track working tool assembly for the lateral adjustment. As is known, the assembly may be glidably moved transversely of the track, or be pivotal for lateral movement.

In track tampers wherein the track tramping tools are designed to tamp the ballast under the ties and to compact it particularly underneath the points where the rails rest on the ties to provide a solid support for the track, it is desirable to move the tamping tools as closely as possible to the flange of the adjacent rail so that the tools immersed in the ballast will operate close to the rails. This obviously requires a fine lateral adjustment of the tamping tool unit in respect of the rail with which it is associated. Furthermore, the tamping tool unit must be laterally adjusted in track curves to prevent the tamping tools from hitting the rails when they are immersed in theballast, thus causing possible damage to the tools and/or the track.

For this purpose, it has been proposed to provide a drive means for the lateral adjustment of track tamping units and other track tamping tool assemblies so that the assembly may be slid or pivoted laterally into positions adjusted in relation to the track. Such lateral adjustment drives have been manually operated, requiring careful attention and skill of the operator to obtain the desired positioning of the assembly. Usually, in track working operations, the operator of the machine has to supervise a number of operations, and visibility is often obstructed. Accordingly, manual operation has often made it unavoidable for the tools and the rails to collide/Also, the lateral adjustment could be effected only after the machine has been stopped between the intermittent tamping movements during each one of which a tie or a group of ties is tamped. This causes delays in the tamping operation which advances intermittently from tie to tie, or group of ties to group of ties in the well known automated tamping procedures of recent years. The lateral adjustment was particularly cumbersome and time-consuming with switch tampers at widened track switching points.

It is the primary object of this invention to overcome the above and other disadvantages, and to provide a fully automatic and highly dependable control for the lateral adjustment of track working tool assemblies.

The above and other objects and advantages are accomplished in accordance with the invention with a control apparatus which comprises a sensor associated with the track working tool assembly and arranged to sense the lateral position of the track in respect of the track working tool assembly as the machine moves on the track rails. The sensor includes means for producing electrical control signals corresponding to the sensed lateral track position. An adjustable control de vice for the track tool assembly moving drive is electrically connected to the sensor and continuously receives the control signals. In this manner, the control signals adjust the control device in response to the control signals for moving the track working tool assembly laterally responsively to the control signals.

This enables the track working tool assembly to be constantly centered accurately in respect of the associated track rail so that the track working tools of the assembly always have the desired distance from the rail and cannot damage the same, or be damaged thereby, when the tools are lowered. Furthermore, since the control signals are produced while the machine advances along the track, the lateral adjustment involves no time losses, thus increasing the efficiency of the machine substantially.

According to a preferred embodiment, the sensor is constituted by an induction switch arranged laterally adjacent, but spaced from, the head of at least one of the track rails at respective sides of the rail, each of the induction switches having a contact inductively operable by a variation in the lateral distance between the switch and the adjacent rail head. Such a sensor is sensitive to deviations in the lateral track position and constitutes a compact control unit which is neither subject to frictional wear nor to weather or other atmospheric conditions.

The spacing of the induction switches is preferably so selected that the contacts will be inductively operated only when the lateral deviation of the rail exceeds a given parameter or tolerance so that the control will not be operative within the admissible tolerance. This prevents a constant opening and closing of the contacts at very slight variations in the course of the track.

It is very useful if the advance of the machine along the track also is controlled by the inductively operable sensor. For this purpose, each induction switch may have another contact inductively operated by the spaced rail fastening elements, which are spaced along the track elongation, for moving the machine frame on the track in response to the operation of the other contact. In this manner, a single control will automatically determine the advance of the machine on the track and the lateral adjustment of the track working tool assembly.

According to another preferred embodiment, the sensor comprises a further induction switch arranged laterally adjacent, but outwardly spaced from, each of the first-named induction switches. Means is provided for switching off the further induction switches when the first-named switches are electrically connected to the drive while the machine advances along a regular track section, and for electrically connecting the further switches to the drive in special track sections, such as at switch points, when the first-named switches are switched off. In this manner, the further induction switches make it possible accurately to center the track working tool assembly in respect of the switch or the divergent track rails at the switch point. Such further selectively operable switches are also useful in track sections of increased gauge.

While an electromotor operating a threaded spindle for laterally adjusting the track working tool assembly may be used as a drive for the lateral adjustment of the assembly, the preferred drive is a double-acting hydraulic motor. Such motors are operated by a hydraulic fluid circuit including a source of hydraulic fluid, a fluid supply line leading from the fluid source to one chamber of the hydraulc motor, fluid return line leading from the other chamber of the hydraulic motor to the fluid source, and a constant-speed fluid pump in the fluid supply line. In this case, the adjustable control device comprises a solenoid valve in the hydraulic circuit.

The solenoid valve has a coil electrically connected to the sensor and actuated by the control signals.

Usually, each track rail has one of the track working tool assemblies associated therewith, and the drive may be arranged to move both assemblies or separate drives may be provided for each assembly, the latter arrangement being preferred for switch tampers where it is necessary to adjust the tamper units independently.

The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of certain now preferred embodiments thereof taken in conjunction with the accompanying drawing wherein FIG. 1 is a schematic elevational side view of a mobile track tamping, leveling and lining incorporating the control of this invention;

FIGS. 2 and 3 are enlarged side elevational views of a portion of the machine of FIG. 1 and of a switch tamper, respectively;

FIGS. 4 and 5 are respective schematic top view of FIGS. 2 and 3;

FIG. 6 shows a circuit diagram of the control circuit for the control; and

FIG. 7 is a schematic transverse section of a sensor according to the invention.

Referring now to the drawing, wherein like reference numerals designate like parts operating in an equivalent rnanner in all figures, FIG. 1 shows a track tamping, leveling and lining machine whose elongated frame 3 is mounted for mobility on the track rails 7, 7 by running gears 1 and 2 supporting the front and rear ends of the machine frame. A series of track working tool assemblies are mounted on machine frame 3 intermediate the running gears, the illustrated assemblies including a tamping tool unit 4, a track lifting unit 5 and a track lining unit 6. The machine moves along the track in the direction of arrow A.

Machines of this type are well known and the operating parts are, therefore, not described in detail, including the track position measuring bogies 8, 9 and 10 which normally run on the track rails but may be raised when not in operation. In these known machines and as shown herein, the track leveling or grading operations are controlled by a reference 11 extending between front measuring bogie 8 and rear measuring bogie 10, this reference being constituted, for instance, by two reference lines extending vertically above each rail and thus defining a reference plan parallel to the desired plane of the track. A track position sensor 12 is associated with the intermediate measuring bogie 9 and is arranged to cooperate with the reference to control the operation of the track lifting unit 5 in a known manner. An equally known reference system for the control of the track lining unit 6 is also provided but not shown in the drawing to simplify the illustration.

In a conventional machine as hereinabove described, the present invention provides a control for the lateral adjustment of the tamping tool unit 4. As indicated hereinabove, the tamping tools 4a must be centered accurately in respect of each associated rail "7 to avoid collisions between the tools and the rail. For this purpose, each tamping tool unit 4 is laterally movably mounted in transverse guide rails 13, a hydraulic drive motor 14 being provided for laterally moving each unit laterally transversely of the track.

A sensor 15 is associated with each track tamping unit 4 and is arranged to sense the lateral position of the track in respect of this unit as the machine moves on the track rails. The sensor includes means for producing electrical control signals corresponding to the sensed lateral track position.

If desired, such a sensor may be constituted by a potentiometer whose vertical rotary shaft carries a sensing arm whose free end contacts the adjacent rail. When the rail deviates from a straight path, i.e. the distance between the rotary axle and the rail varies, the arm will be pivoted by the deviating rail to change the voltage, thus producing a control signal corresponding to the lateral rail position.

However, in the preferred illustrated embodiment, the sensor is constituted by a pair of induction switches l5, 15 arranged laterally adjacent, but spaced from, the head 7a of the associated track rail at respective sides thereof. The spacing of the induction switches from the rail head 7a is so selected as to avoid a constant operation of the switch contacts, i.e. the magnetic induction caused by the ferrous rail becomes effective only when the distance variation exceeds a given tolerance. The induction switches are mechanically connected to, or mounted on, the laterally movable tamping tool carrier 16 on which the tools 4a are vertically adjustably mounted. In this manner, the induction switches move laterally with the tamping tool unit with which it is associated and whose lateral movement it is designed to control. If desired, the position of the induction switches on the tamping tool carrier 16 may be adjustable so that the spacing of the induction switches in respect of rail head 7a may be varied.

Induction switches are readily obtainable articles of commerce, the structure and operation being substantially as follows:

Each induction switch comprises a two-armed switching lever pivotal about a centrally positioned fulcrum and carrying a switching contact element at each end. Mounted in the range of the pivotal contact elements of the switch are cooperating fixed contact elements each associated with a permanent magnet creating a magnetic field about the respective fixed contact elements. One of the magnets is farther removed from the associated fixed contact element than the other magnet so that the magnetic field surrounding the one fixed contact element is weaker than the magnetic field of the other fixed contact element. The stronger magnetic field is of sufficient intensity normally to attract its cooperating pivotal contact element so that the one contact of the switch is normally closed while the weaker intensity of the magnetic field surrounding the other fixed element permits its cooperating pivotal contact element to keep the other contact of the switch open.

When a ferrous member, such as the rail head 7a laterally adjacent a switch, comes closer to the closed contact, i.e. in a track section where the rail deviates from its straight course, it weakens the intensity of the magnetic field keeping the contact closed. When the magnetic field intensity is reduced sufficiently to become less than that of the field of the opposite open switch contact as the ferrous member moves beyond a set tolerance, the normally open switch contact will be closed as the normally closed contact is opened. The normally open switch contact is electrically connected to a control circuit so that its closing will close the circuit to produce the desired control signal.

In this manner, as the lateral position of rail 7 changes either towards the right or the left beyond a set tolerance, the normally open contact of the right or left switch will be closed to actuate the control circuit electrically connected to the control device for laterally moving the tamping tool unit 4 to maintain a constant distance between the rail head 7a and the tamping tools 4a as the machine advances along the track.

The functioning of the specific control herein described will be further elucidated hereinbelow in connection with FIG. 6.

As best shown in FIG. 4, the tamping tool units 4 associated with each rail 7 in the conventional tamping, leveling and lining machine illustrated in FIGS. 1 and 2 are laterally movable transversely of the track by a common double-acting hydraulic drive motor 14 arranged between the tamping units and having the respective piston rods connected to the units so as to move them in unision from a normal lateral position (shown in broken lines) in a straight track section to an offset position (shown in full lines) in a track curve.

FIGS. 3 and 5 show the arrangement in a switch tamper wherein each switch tamping tool unit 412, with its operating station 17, is independently laterally movable by respective hydraulic motors 14a, 14b connected thereto. To make fine adjustment at switch points more effective, the piston rods of the hydraulic drive motors are linked to one end of the respective tamper units so that the units may not only be moved perpendicularly to the track in a transverse direction but also pivoted about respective fulcrums 18 of each unit so that the units may be pivoted on the frame.

As shown in FIG. 3, the frame 3 of the switch tamper runs on wheels 19 and supports a measuring bogie 20 coordinated with a reference 21 in a known manner. A transverse guide rail 22 supports the tamping tool carriers 23 for lateral movement, all of these structures being conventional in switch tampers.

FIG. 6 illustrates a useful control arrangement according to the invention. As shown, a pair of induction switches l5, 15 are laterally adjacent, but spaced from, the head 7a of rail 7 of respective sides thereof. The above-described normally open contact of each switch 15 is electrically connected with a respective coil 24, 24 of solenoid valve 25. Since the control signal produced by the closing of the contact may be weak, it will be advantageous to mount amplifiers 26, 26 in the electrical connection between the switches and the solenoid valve coils, as shown.

The double-acting hydraulic drive motor 14, which moves the tamping unit 4 in the direction of the doubleheaded arrow, is operable by a hydraulic fluid circuit which includes a hydraulic fluid sump 29, a fluid supply line 28 leading from the sump to one chamber of the motor 14, a fluid return line 30 leading from the other motor chamber to sump 29, and a constant-speed pump 27 in fluid supply line 28. The solenoid valve is arranged in the hydraulic circuit as a control device for controlling the fluid flow for operating the drive 14.

When the rail head 7a moves beyond its tolerance limit towards one of the switches 15, the normally open contact of the one switch will be closed to generate a control signal activating the connected solenoid valve coil 24 and operating the valve so that the doubleacting piston of motor 14 will be moved away from the rail head until the one switch has assumed its previous spacing from the rail head, at which point the normally open contact will resume its open position, the control signal will cease and the lateral movement of the tamping unit will stop. In this manner, the tamping unit 4 remains constantly and automatically centered in respect of the associated rail 7.

FIG. 7 ilustrates an embodiment wherein the sensor associated with each track working tool assembly and corresponding rail 7 comprises a further induction switch 15a, 15a arranged laterally adjacent, but outwardly spaced from, each switch 15, 15. Where there are double rails, such as at switch points (see FIG. 5), the switches 15, 15 are switched off, i.e. electrically disconnected from the control circuit while the switches 15a, 15a are electrically connected to the drive while the switches 15a, 15a remain switched off in normal track sections.

As indicated in FIG. 7, it is also possible to associate each of the induction switches 15, 15 mounted in a single housing with a pair of magnets so that the switches serve to control different operations of the machine. In such an arrangement, the magnetic fields whose intensity is influenced by the approach of a ferrous member emanate from different walls of the switch housing. Thus, the lateral housing wall 31 may have associated therewith the magnetic field of the normally open switch contact described hereinabove for the control of the lateral adjustment drive 14 of the tamping unit. Another magnetic field is associated with bottom housing wall 32 and the normally open switch contact operated by the other magnetic field is inductively operated by a respective rail fastening element 7b when the latter comes close enough thereto. The resultant control signal may be used for operating the forward drive of the machine, i.e. as soon as the induction switch contact at wall 32 comes close enough to a respective rail fastening element. i.e.. a track tie, its corresponding control signal will operate the brake and release the clutch of the machine so as to stop the machine, thus centering the tamping tools over the ties and hold them symmetrically in respect thereto.

We claim:

1. An apparatus for controlling the lateral adjustment of a track working tool assembly mounted on the frame of a track working machine for lateral movement transversely of the track relative to the frame, the machine frame being mounted for mobility on the track rails, and a drive being provided for laterally moving the track tool assembly for said adjustment, the control apparatus comprising 1. a sensor associated with the track working tool assembly and arranged to sense the lateral position of the track in respect of the track working tool assembly as the machine frame moves on the track rails,

a. the sensor including means for producing electrical control signals corresponding to the sensed lateral track position, and 2. an adjustable control device for the track tool assembly moving drive electrically connected to the sensor and continuously receiving the control signals,

a. the control signals adjusting the control device in response to the control signals for moving the track working tool assembly laterally responsively to the control signals.

2. The apparatus of claim 1, wherein the track working tool assembly is a track tamping unit.

3. The apparatus of claim 2, wherein each of the track rails has one of the track tamping units associated therewith, and the drive is arranged to move both assemblies.

4. The apparatus of claim 2, wherein each of the track rails has one of the track tamping units associated therewith, and a separate one of the drives is provided for each of the assemblies.

5. The apparatus of claim 1, wherein the track working tool assembly is pivotal for lateral movement transversely of the track.

6. The apparatus of claim 1, wherein the sensor is constituted by an induction switch arranged laterally adjacent, but spaced from, the head of at least one of the track rails at respective sides of the rail, each of the induction switches having a contact inductively operable by a variation in the lateral distance between the switch and the adjacent rail head.

7. The apparatus of claim 6, wherein the track comprises rail fastening elements spaced along the track elongation, and the induction switch has another contact inductively operated by the spaced rail fastening elements for moving the machine frame on the track in response to the operation of the other contact.

'8. The apparatus of claim 6, wherein the sensor comprises a further induction switch arranged laterally adjacent, but outwardly spaced from, each of the firstnamed induction switches, and means for switching off the further induction switches when the first-named switches are electrically connected to the drive and for electrically connecting the further switches to the drive when the first-named switches are switched off.

9. The apparatus of claim 1, wherein the drive comprises a double-acting hydraulic motor operable by a hydraulic fluid circuit, the hydraulic circuit including a source of hydraulic fluid, a fluid supply line leading from the fluid source to one chamber of the hydraulic motor, a fluid return line leading from the other chamber of the hydraulic motor to the fluid source, and a constant-speed fluid pump in the fluid supply line, and the adjustable control device comprises a solenoid valve in the hydraulic circuit, the solenoid valve having a coil electrically connected to the sensor and actuated by the control signals.

10. The apparatus of claim 9, further comprising an amplifier connected between the sensor and the solenoid valve coil for amplifying the control signals. 

1. An apparatus for controlling the lateral adjustment of a track working tool assembly mounted on the frame of a track working machine for lateral movement transversely of the track relative to the frame, the machine frame being mounted for mobility on the track rails, and a drive being provided for laterally moving the track tool assembly for said adjustment, the control apparatus comprising
 1. a sensor associated with the track working tool assembly and arranged to sense the lateral position of the track in respect of the track working tool assembly as the machine frame moves on the track rails, a. the sensor including means for producing electrical control signals corresponding to the sensed lateral track position, and
 2. an adjustable control device for the track tool assembly moving drive electrically connected to the sensor and continuously receiving the control signals, a. the control signals adjusting the control device in response to the control signals for moving the track working tool assembly laterally responsively to the control signals.
 2. The apparatus of claim 1, wherein the track working tool assembly is a track tamping unit.
 2. an adjustable control device for the track tool assembly moving drive electrically connected to the sensor and continuously receiving the control signals, a. the control signals adjusting the control device in response to the control signals for moving the track working tool assembly laterally responsively to the control signals.
 3. The apparatus of claim 2, wherein each of the track rails has one of the track tamping units associated therewith, and the drive is arranged to move both assemblies.
 4. The apparatus of claim 2, wherein each of the track rails has one of the track tamping units associated therewith, and a separate one of the drives is provided for each of the assemblies.
 5. The apparatus of claim 1, wherein the track working tool assembly is pivotal for lateral movement transversely of the track.
 6. The apparatus of claim 1, wherein the sensor is constituted by an induction switch arranged laterally adjacent, but spaced from, the head of at least one of the track rails at respective sides of the rail, each of the induction switches having a contact inductively operable by a variation in the lateral distance between the switch and the adjacent rail head.
 7. The apparatus of claim 6, wherein the track comprises rail fastening elements spaced along the track elongation, and the induction switch has another contact inductively operated by the spaced rail fastening elements for moving the machine frame on the track in response to the operation of the other contact.
 8. The apparatus of claim 6, wherein the sensor comprises a further induction switch arranged laterally adjacent, but outwardly spaced from, each of the first-named induction switches, and means for switching off the further induction switches when the first-named switches are electrically connected to the drive and for electrically connecting the further switches to the drive when the first-named switches are switched off.
 9. The apparatus of claim 1, wherein the drive comprises a double-acting hydraulic motor operable by a hydraulic fluid circuit, the hydraulic circuit including a source of hydraulic fluid, a fluid supply line leading from the fluid source to one chamber of the hydraulic motor, a fluid return line leading from the other chamber of the hydraulic motor to the fluid source, and a constant-speed fluid pump in the fluid supply line, and the adjustable control device comprises a solenoid Valve in the hydraulic circuit, the solenoid valve having a coil electrically connected to the sensor and actuated by the control signals.
 10. The apparatus of claim 9, further comprising an amplifier connected between the sensor and the solenoid valve coil for amplifying the control signals. 